Why Wind Does More Harm Than Cold

Most shrubs sold in British nurseries are perfectly capable of surviving our winter temperatures. What finishes them off is the wind. A plant rated hardy to -10°C can be stripped and blackened at -3°C if it is sitting in a 40mph gale, because moving air drags heat out of leaf tissue far faster than still air ever does. That is wind chill in its most practical, garden-destroying form.

Evergreens are the most vulnerable. They hold their leaves right through the winter, and those leaves continue to transpire even when the ground is frozen solid and the roots cannot possibly replace the moisture lost. The result is the classic case of winter burn: a camellia, choisya or pittosporum with crisp brown foliage along its windward side and perfectly healthy leaves everywhere else. Add salt-laden gales on the coast, or the rocking that loosens a young rootball in the ground, and you have three separate problems caused by one thing.

A Solid Barrier Makes Things Worse

The instinct is to build the tallest, most impermeable wall you can afford. Resist it. A solid fence or wall forces the wind up and over, and where it comes back down it lands as a turbulent, accelerated gust. The turbulence is often worse than the original breeze, and it arrives precisely where your delicate shrub is sitting. A solid barrier in a gale also behaves like a sail, which is why so many close-board fences end up flat on a lawn after a storm.

What you want instead is a porous barrier with roughly 40 to 50 per cent open area. Wind passes through it, is slowed and filtered, and emerges as a gentler, more even flow instead of a battering pulse. A good porous windbreak protects a zone extending downwind roughly ten times its own height. A solid one protects less, and ruins the air quality behind it.

Choosing Your Barrier Material

Happily, the porous options are also the ones that look right in a British garden. Woven hazel or willow hurdles are the classic choice, and a well-made hurdle on stout posts will give you seven to ten years before it needs replacing. Chestnut paling, reed screens and slatted timber fencing all do the same job, and all of them let a proportion of the wind through.

• Woven hurdles — warm, natural, brilliant against a bare border in January. Fix to posts rather than trying to free-stand them.
• Reed or brushwood screens — good for coastal gardens and for wrapping a specific plant rather than a whole boundary.
• Slatted fencing — choose a gap of 25–50mm between boards. Look at it from the side; if you can see plenty of daylight, the porosity is about right.
• Knitted windbreak netting — cheap, effective and deeply ugly, but invaluable as a temporary screen around newly planted evergreens for their first two winters.

Whatever you choose, use a single layer. Doubling up panels reduces airflow to the point where the barrier behaves like a solid wall, and you lose the benefit you paid for.

Positioning and Height

Work out where the prevailing wind comes from — in most of the UK that is south-west, though exposed eastern coasts and upland sites will differ. Site the barrier perpendicular to that direction, not wrapped tightly around the plant.

Height matters more than length. For a typical garden, 1.5m to 2m is enough to shelter low and medium shrubs, and the protected zone will stretch downwind for 15–20m. Leave a gap of at least 30–60cm under the bottom of the barrier. That gap lets ground-level air escape and dramatically reduces the eddying that otherwise forms behind it. If your barrier sits on a slope, stagger it into two shorter runs rather than one long one, and never leave a funnel-shaped gap between barrier and boundary, which simply accelerates the wind straight at the plants you are trying to save.

Living Windbreaks That Earn Their Keep

A hedge is a permanent, self-repairing windbreak, and a mixed one outperforms a single species because different plants fail at different times. For most of the country, a blend of hawthorn, blackthorn, hazel, field maple and holly gives you dense, semi-evergreen cover within four or five years. Beech and hornbeam hold their dead leaves through winter when clipped, which makes them surprisingly effective.

If you want a fully evergreen screen, yew is the gold standard — slow, long-lived and tolerant of hard clipping. For coastal sites, griselinia, escallonia and Elaeagnus work well, while Viburnum tinus and Pittosporum suit milder, sheltered gardens. Plant a double staggered row at 45cm spacing for a stock-proof barrier, and keep the hedge informally shaped: tight box-like clipping produces a dense outer shell with a hollow, draughty base.

Keeping the Protection Working

A windbreak is only as good as its fixings. Check posts and ties after every named storm, and re-tension netting that has sagged. Replace rotten posts in late autumn rather than waiting for the first gale to do it for you.

For living hedges, prune in late winter or early spring and avoid cutting between March and August, when nesting birds are legally protected. Mulch along the base to stop grass and weeds competing with young hedging plants, and water them properly through their first two summers — a windbreak that dies of drought has protected nothing.

Finally, remember that wind protection is not only a winter concern. A barrier that slows spring gales will protect soft new growth, help pollinating insects work in peace, and stop your best shrubs from being sandblasted by salt and grit. Build it porous, build it in the right place, and it will pay you back for years.